Fluid-filled bladder for footwear and other applications

ABSTRACT

A fluid-filled structure, such as a bladder, is disclosed. The bladder has a first surface and an opposite second surface that are peripherally joined to define various edges. The bladder encloses a fluid between the first surface and the second surface. A portion of the edges may have a concave configuration, or the edges may have both concave and convex configurations. A shape of the bladder may be a tessellation pattern so that a plurality of the bladder may be efficiently. The edges may also have a linear configuration, and the bladder may enclose a tensile member.

CROSS-REFERENCE TO RELATED APPLICATION

This U.S. Patent Application is a continuation application of and claimspriority to U.S. application Ser. No. 11/216,533, which was filed in theU.S. Patent and Trademark Office on Aug. 30, 2005 and entitled“Fluid-Filled Bladder For Footwear And Other Applications” (now U.S.Pat. No. 7,513,066), which application is a continuation-in-partapplication of and claims priority to U.S. patent application Ser. No.11/107,354, which was filed in the U.S. Patent and Trademark Office onApr. 14, 2005 and entitled “Fluid-Filled Bladder For Footwear And OtherApplications” (now U.S. Pat. No. 7,401,369), such prior U.S. PatentApplication being entirely incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to fluid-filled structures. The inventionconcerns, more particularly, a bladder that encloses a pressurized fluidand is suitable for various commodities, including articles of footwear.

2. Description of Background Art

Fluid-filled structures, such as bladders, are utilized in a variety ofcommodities. For example, fluid-filled structures may be utilized aspacking materials, to impart comfort to a backpack or golfbag strap, orto enhance the comfort of seat cushions. One application wherefluid-filled structures have gained particular acceptance is footwear.

A conventional article of athletic footwear includes two primaryelements, an upper and a sole structure. The upper provides a coveringfor the foot that securely receives and positions the foot with respectto the sole structure. In addition, the upper may have a configurationthat protects the foot and provides ventilation, thereby cooling thefoot and removing perspiration. The sole structure is secured to a lowersurface of the upper and is generally positioned between the foot andthe ground. In addition to attenuating ground reaction forces, the solestructure may provide traction and control foot motions, such as overpronation. Accordingly, the upper and the sole structure operatecooperatively to provide a comfortable structure that is suited for awide variety of ambulatory activities, such as walking and running.

The sole structure of athletic footwear generally exhibits a layeredconfiguration that includes a comfort-enhancing insole, a resilientmidsole formed from a polymer foam, and a ground-contacting outsole thatprovides both abrasion-resistance and traction. Suitable polymer foammaterials for the midsole include ethylvinylacetate or polyurethane thatcompress resiliently under an applied load to attenuate ground reactionforces. Conventional polymer foam materials are resilientlycompressible, in part, due to the inclusion of a plurality of open orclosed cells that define an inner volume substantially displaced by gas.That is, the polymer foam includes a plurality of bubbles that enclosethe gas. Following repeated compressions, the cell structure maydeteriorate, thereby resulting in decreased compressibility of the foam.Accordingly, the force attenuation characteristics of the polymer foammidsole may decrease over the lifespan of the footwear.

One manner of reducing the weight of a polymer foam midsole anddecreasing the effects of deterioration following repeated compressionsis disclosed in U.S. Pat. No. 4,183,156 to Rudy, hereby incorporated byreference, in which force attenuation is provided by a fluid-filledbladder formed of an elastomeric materials. The bladder includes aplurality of tubular chambers that extend longitudinally along a lengthof the sole structure. The chambers are in fluid communication with eachother and jointly extend across the width of the footwear. The bladdermay be encapsulated in a polymer foam material, as disclosed in U.S.Pat. No. 4,219,945 to Rudy, hereby incorporated by reference. Thecombination of the bladder and the encapsulating polymer foam materialfunctions as a midsole. Accordingly, the upper is attached to the uppersurface of the polymer foam material and an outsole or tread member isaffixed to the lower surface.

Bladders of the type discussed above are generally formed of anelastomeric material and are structured to have an upper and lowerportions that enclose one or more chambers therebetween. The chambersare pressurized above ambient pressure by inserting a nozzle or needleconnected to a fluid pressure source into a fill inlet formed in thebladder. Following pressurization of the chambers, the fill inlet issealed and the nozzle is removed.

Fluid-filled bladders suitable for footwear applications may bemanufactured by a two-film technique, in which two separate sheets ofelastomeric film are formed to exhibit the overall peripheral shape ofthe bladder. The sheets are then bonded together along their respectiveperipheries to form a sealed structure, and the sheets are also bondedtogether at predetermined interior areas to give the bladder a desiredconfiguration. That is, the interior bonds provide the bladder withchambers having a predetermined shape and size. In a similarthermoforming technique, the two separate sheets of elastomeric film areshaped with a mold to exhibit a desired configuration. Fluid-filledbladders suitable for footwear applications may also be manufactured bya blow-molding technique, wherein a molten or otherwise softenedelastomeric material in the shape of a tube is placed in a mold havingthe desired overall shape and configuration of the bladder. The mold hasan opening at one location through which pressurized air is provided.The pressurized air induces the liquefied elastomeric material toconform to the shape of the inner surfaces of the mold. The elastomericmaterial then cools, thereby forming a bladder with the desired shapeand configuration.

SUMMARY OF THE INVENTION

One aspect of the invention is a bladder with a first surface and anopposite second surface that are peripherally joined to define variousedges. The bladder encloses a pressurized fluid between the firstsurface and the second surface. In some embodiments, the bladder has atessellation configuration and encloses a tensile member. In otherembodiments, the bladder has a hexagonal shape.

The bladder may be incorporated into an article of footwear having anupper and a sole structure. For example, the bladder may be encapsulatedwithin a polymer foam material of the sole structure, or the bladder maybe located within a void that is formed in the polymer foam material.Alternately, the bladder may be located within the upper.

Another aspect of the invention involves a method of manufacturing aplurality of bladders. The method includes a step of providing a firstsheet and a second sheet of a thermoplastic polymer material. Tensilemembers are located between and joined with the first sheet and thesecond sheet. Bonds may be formed between the first sheet and the secondsheet and around the tensile members to define the bladders. In additiona portion of the bonds may be bisected and a pressurized fluid may beplaced within the bladders.

The advantages and features of novelty characterizing the presentinvention are pointed out with particularity in the appended claims. Togain an improved understanding of the advantages and features ofnovelty, however, reference may be made to the following descriptivematter and accompanying drawings that describe and illustrate variousembodiments and concepts related to the invention.

DESCRIPTION OF THE DRAWINGS

The foregoing Summary of the Invention, as well as the followingDetailed Description of the Invention, will be better understood whenread in conjunction with the accompanying drawings.

FIG. 1 is a side elevational view of an article of footwearincorporating a bladder.

FIG. 2 is a partial cut-away side elevational view of the footwear.

FIG. 3 is a perspective view of the bladder.

FIG. 4 is a top plan view of the bladder.

FIG. 5 is a bottom plan view of the bladder.

FIG. 6A is a first cross-sectional view of the bladder, as defined bysection line 6A-6A in FIG. 4.

FIG. 6B is a second cross-sectional view of the bladder, as defined bysection line 6B-6B in FIG. 4.

FIG. 6C is a third cross-sectional view of the bladder, as defined bysection line 6C-6C in FIG. 4.

FIG. 7 is a top plan view of a plurality of the bladder in a joinedconfiguration.

FIG. 8 is a top plan view of corresponding mold portions that form thebladder and a plurality of other bladders.

FIG. 9A is a schematic side elevational view of a first step in amanufacturing process of the bladder and the plurality of otherbladders.

FIG. 9B is a schematic side elevational view of a second step in amanufacturing process of the bladder and the plurality of otherbladders.

FIG. 9C is a schematic side elevational view of a third step in amanufacturing process of the bladder and the plurality of otherbladders.

FIG. 10 is a top plan view of another configuration of the bladder.

FIG. 11 is a top plan view of another configuration of the bladder.

FIG. 12 is a perspective view of a tensile bladder.

FIG. 13 is a top plan view of the tensile bladder.

FIG. 14A is a first cross-sectional view of the tensile bladder, asdefined by section line 14A-14A in FIG. 13.

FIG. 14B is a second cross-sectional view of the tensile bladder, asdefined by section line 14B- 14B in FIG. 13.

FIG. 15 is a top plan view of a plurality of the tensile bladder in ajoined configuration.

DETAILED DESCRIPTION OF THE INVENTION

The following discussion and accompanying figures disclose an article ofathletic footwear incorporating a fluid-filled bladder. The footwear isdisclosed as having a configuration that is suitable for running.Aspects of the invention are not solely limited to footwear designed forrunning, however, and may be applied to a wide range of athleticfootwear styles, including basketball shoes, cross-training shoes,walking shoes, tennis shoes, soccer shoes, and hiking boots, forexample. In addition, aspects of the invention may be applied tofootwear styles that are generally considered to be non-athletic,including dress shoes, loafers, sandals, and work boots. Although thebladder is disclosed in combination with footwear, the bladder may beutilized in a variety of other products, or the bladder may be utilizedalone (e.g., as a packing material). Accordingly, one skilled in therelevant art will appreciate that the concepts disclosed herein apply toa wide variety of footwear styles and products.

An article of footwear 10 is depicted in FIGS. 1 and 2 as including anupper 20 and a sole structure 30. Upper 20 has a substantiallyconventional configuration and includes a plurality elements, such astextiles, foam, and leather materials, that are stitched or adhesivelybonded together to form an interior void for securely and comfortablyreceiving the foot. Sole structure 30 is positioned below upper 20 andincludes two primary elements, a midsole 31 and an outsole 32. Midsole31 is secured to a lower surface of upper 20 through stitching oradhesive bonding, for example, and operates to attenuate forces as solestructure 30 impacts the ground. Outsole 32 is secured to a lowersurface of midsole 31 and is formed of a durable, wear-resistantmaterial that is suitable for engaging the ground. Outsole 32 may beabsent in some embodiments of the invention, or outsole 32 may be formedof unitary (i.e., one piece) construction with midsole 31. In addition,sole structure 30 may include an insole (not depicted), which is a thincomfort-enhancing member, located within the void and adjacent to theplantar surface of the foot.

Midsole 31 is primarily formed of a polymer foam material, such aspolyurethane or ethylvinylacetate, that encapsulates a fluid-filledbladder 40. As depicted in FIG. 2, bladder 40 is positioned in a heelregion of midsole 31, but may be positioned in any region of midsole 31,including a midfoot region or a forefoot region. Furthermore, midsole 31may encapsulate multiple fluid-filled bladders having the generalconfiguration of bladder 40. For example, one bladder 40 may be locatedin the heel region and a separate bladder 40 may be located in theforefoot region of footwear 10.

Bladder 40 may be only partially encapsulated within midsole 31 orentirely encapsulated within midsole 31. For example, portions ofbladder 40 may protrude outward from a side surface of midsole 31, or anupper surface of bladder 40 may coincide with an upper surface ofmidsole 31. Alternately, midsole 31 may extend over and entirely aroundbladder 40. In some embodiments, bladder 40 may be adhesively secured tomidsole 31, or bladder 40 may be located within a pre-made void inmidsole 31, for example. In other embodiments, bladder 40 may beincorporated into upper 20 or the insole. For example, bladder 40 may belocated within a heel area of the insole or a forefoot area of theinsole. Accordingly, the position of bladder 40 with respect to footwear10 may vary significantly within the scope of the invention.

Bladder 40 is a sealed member that encloses a pressurized fluid, asdepicted in FIGS. 3-6C. The material forming bladder 40, which will bediscussed in greater detail below, is substantially impermeable to thefluid and forms a first surface 41 and an opposite second surface 42.First surface 41 and second surface 42 are bonded together around theirrespective peripheries to form a peripheral bond 43 and cooperativelyform a sealed chamber, in which the pressurized fluid is located. Asdepicted in the figures, peripheral bond 43 is centered between firstsurface 41 and second surface 42, but may also be in a non-centeredlocation. Accordingly, the specific location of peripheral bond 43 mayvary.

The general shape of bladder 40, as depicted in FIGS. 4 and 5, ishexagonal. Peripheral bond 43 effectively forms six edges 51-56 thatsequentially extend around bladder 40.

That is, edge 51 is positioned adjacent to edge 52, edge 52 ispositioned adjacent to edge 53, edge 53 is positioned adjacent to edge54, edge 54 is positioned adjacent to edge 55, edge 55 is positionedadjacent to edge 56, and edge 56 is positioned adjacent to edge 51. Eachof edges 51, 53 and 55 extend outward to impart a convex configurationto these portions of peripheral bond 43. In contrast, each of edges 52,54, and 56 extend inward to impart a concave configuration. Whereas edge56 has an inwardly-rounded shape, each of edges 52 and 54 also form afurther indentation 57 that extends closer to a central portion ofbladder 40. That is, indentations 57 of each of edges 52 and 54 protrudecloser to the central portion of bladder 40 than edge 56.

As discussed above, each of edges 51, 53 and 55 extend outward to imparta convex configuration to these portions of peripheral bond 43. Inaddition, each of edges 52, 54, and 56 extend inward to impart a concaveconfiguration. Given this configuration and the locations of each ofedges 51-56, the convex portions of peripheral bond 43 alternate withthe concave portions of peripheral bond 43. That is, every other edge ofbladder 40 is convex, and the other edges are concave. This structureimparts a tri-lobed configuration to bladder 40, wherein each of edges51, 53, and 55 form ends of the three lobes. Alternately, bladder 40 maybe viewed as having a hexagonal configuration that includes three convexedges 51, 53, and 55 alternating with three concave edges 52, 54, and56.

Bladder 40 has a configuration wherein first surface 41 and secondsurface 42 are devoid of internal connections in the central portion ofbladder 40. That is, peripheral bond 43, which is located at theperiphery of bladder 40, forms the primary points where first surface 41and second surface 42 are bonded or otherwise connected to each other.As depicted in the figures, however, an inflation bond 44 is formedadjacent to the periphery of bladder 40. More particularly, inflationbond 44 is formed adjacent to edge 56, but may be formed adjacent to anyof edges 51-56. Inflation bond 44 extends parallel to edge 56, and aninflation area 45 is centrally located with respect to inflation bond44. As will be described in greater detail in the following material, aninflation needle, inflation nozzle, inflation electrode, or otherinflation device may be coupled to inflation area 45 to inject thepressurized fluid. The fluid then passes through a conduit formedbetween peripheral bond 43 and inflation bond 44. Once bladder 40 isproperly inflated with the fluid, inflation area 45 is sealed to sealthe fluid within bladder 40. In order to permit the central portion ofbladder 40 to expand outward, inflation bond 44 may be cut or otherwisebisected to separate the central portion of bladder 40 from the conduitformed between peripheral bond 43 and inflation bond 44. Accordingly,bladder 40 is effectively devoid of internal connections in the centralportion of bladder 40, and inflation bond 44 and inflation area 45 areformed adjacent to the periphery of bladder 40.

As noted above, edge 56 has an inwardly-rounded shape, whereas each ofedges 52 and 54 also form indentations 57. Inflation area 45 iseffectively formed in a location that corresponds with the location ofindentations 57. Accordingly, the portions of bladder 40 adjacent toeach of edges 52, 54, and 55 are bonded in similar locations. The lackof internal connections in the central portion of bladder 40 imparts astructure wherein the central portion of bladder 40 exhibits a greaterthickness than areas adjacent peripheral bond 43, as depicted in FIGS.6A-6C. Accordingly, bladder 40 tapers toward peripheral bond 43.Indentations 57 and inflation area 45 are formed in order to limit thedegree to which the central portion of bladder 40 expands outward. Thatis, indentations 57 and inflation area 45 are formed to limit theoverall thickness of the central portion of bladder 40.

A variety of thermoplastic polymer materials may be utilized for bladder40, including polyurethane, polyester, polyester polyurethane, andpolyether polyurethane. Another suitable material for bladder 40 is afilm formed from alternating layers of thermoplastic polyurethane andethylene-vinyl alcohol copolymer, as disclosed in U.S. Pat. Nos.5,713,141 and 5,952,065 to Mitchell et al, hereby incorporated byreference. A variation upon this material wherein the center layer isformed of ethylene-vinyl alcohol copolymer; the two layers adjacent tothe center layer are formed of thermoplastic polyurethane; and the outerlayers are formed of a regrind material of thermoplastic polyurethaneand ethylene-vinyl alcohol copolymer may also be utilized. Bladder 40may also be formed from a flexible microlayer membrane that includesalternating layers of a gas barrier material and an elastomericmaterial, as disclosed in U.S. Pat. Nos. 6,082,025 and 6,127,026 to Bonket al., both hereby incorporated by reference. In addition, numerousthermoplastic urethanes may be utilized, such as PELLETHANE, a productof the Dow Chemical Company; ELASTOLLAN, a product of the BASFCorporation; and ESTANE, a product of the B.F. Goodrich Company, all ofwhich are either ester or ether based. Still other thermoplasticurethanes based on polyesters, polyethers, polycaprolactone, andpolycarbonate macrogels may be employed, and various nitrogen blockingmaterials may also be utilized. Additional suitable materials aredisclosed in U.S. Pat. Nos. 4,183,156 and 4,219,945 to Rudy, herebyincorporated by reference. Further suitable materials includethermoplastic films containing a crystalline material, as disclosed inU.S. Pat. Nos. 4,936,029 and 5,042,176 to Rudy, hereby incorporated byreference, and polyurethane including a polyester polyol, as disclosedin U.S. Pat. Nos. 6,013,340; 6,203,868; and 6,321,465 to Bonk et al.,also hereby incorporated by reference.

The fluid within bladder 40 may be any of the gasses disclosed in U.S.Pat. No. 4,340,626 to Rudy, hereby incorporated by reference, such ashexafluoroethane and sulfur hexafluoride, for example. The fluid mayalso include gasses such as pressurized octafluorapropane, nitrogen, orair. In addition to gasses, various gels or liquids may be sealed withinbladder 40. Accordingly, a variety of fluids are suitable for bladder40.

With regard to pressure, a suitable fluid pressure is 20 pounds persquare inch, but may range from one to thirty-five pounds per squareinch. Accordingly, the fluid pressure within bladder 40 may berelatively high, or the fluid pressure may be slightly elevated fromambient in some embodiments of the invention.

Bladder 40 may have the configuration of a tessellation. As utilizedherein, the term “tessellation” is defined as a covering of an area,without significant gaps or overlaps, by a plurality of elements havinga substantially similar shape. In addition, an individual element (i.e.,bladder 40) may have the configuration of a tessellation when multiple,similarly-shaped elements cover an area without significant gaps oroverlaps. Bladder 40, when viewed in either of FIGS. 4 and 5, has thegeneral configuration of a tessellation. With reference to FIG. 7, aplurality of bladders 40 are depicted in a joined configuration. Ingeneral, the convex edges (i.e., edges 51, 53, and 55) of one bladder 40extends into the concave edges (i.e., edges 52, 54, and 56) of anadjacent bladder 40, and this is repeated for the plurality of bladders40. In addition, a tab 46 of one bladder 40 extends into the indentation57 of an adjacent bladder 40. As depicted in FIG. 7, therefore, bladder40 has the configuration of a tessellation.

Various shapes, whether hexagonal, rectangular, square, or triangularhave the configuration of a tessellation. Other non-regular shapes mayalso have the configuration of a tessellation. Although bladder 40 isdiscussed above as having a generally hexagonal configuration, bladder40 may also have a variety of other shapes that also have theconfiguration of a tessellation. In some aspects of the invention,however, bladder 40 may have shapes that are not a tessellation.

An advantage to forming bladder 40 in the configuration of atessellation relates to manufacturing efficiency. With reference to FIG.7, the plurality of bladders 40 are depicted in a joined configurationwherein each of bladders 40 is adjacent to other bladders 40. In thisconfiguration, waste in the materials forming bladders 40 is minimized.In some prior art bladders, two sheets of polymer material were bondedtogether and inflated to form an individual bladder. The individualbladder was then cut from the two sheets of polymer material, whichencircled the individual bladder. The remaining portions of the twosheets of polymer material were then discarded. Alternately, theremaining portions of the two sheets of polymer material were recycled(e.g., through a regrind process) to be incorporated into otherbladders. In contrast with this prior art bladders, multiple bladders 40are formed with greater manufacturing efficiency due to the limitedamount of waste product.

Another advantage to forming bladder 40 in the configuration of atessellation relates to energy efficiency. As noted above, the convexedges (i.e., edges 51, 53, and 55) of one bladder 40 extends into theconcave edges (i.e., edges 52, 54, and 56) of an adjacent bladder 40,and this is repeated for the plurality of bladders 40. Each of theconvex edges are formed, therefore with a convex edge in a singlebonding operation. That is, the edges of two adjacent bladders areformed simultaneously to reduce the overall number of bonding operationsthat must occur to form multiple bladders 40, thereby promoting energyefficiency.

In the joined configuration of FIG. 7, a convex edge of a first bladder40 extends into a concave edge of an adjacent second bladder 40.Similarly, a convex edge of the second bladder 40 extends into a concaveedge of an adjacent third bladder 40. Furthermore, a convex edge of thethird bladder 40 extends into a concave edge of the first bladder 40.

In this manner, adjacent bladders 40 are effectively interlocked.Additionally, each bladder 40, with this exception of those located onthe periphery of the joined configuration, are surrounded by sixadjacent bladders 40 with convex edges extending into concave edges.Although the various bladders 40 are joined, the bladders 40 may beseparated by bisecting the bonds between adjacent bladders 40. Asdescribed below, the bonds may be bisected so as to leave relativelysmall portions of the bonds between bladders 40 connected. In thismanner, the plurality of bladders 40 remain joined, but may be pulledapart with minimal effort.

A method of manufacturing the plurality of bladders 40 depicted in FIG.7 will now be discussed. FIG. 8 depicts a mold 60 having a pair ofcorresponding mold portions 61 and 62. Each of mold portions 61 and 62have various ridges 63 that have the general shape of bladder 40. Moreparticularly, ridges 63 have the shape of the various bonds of bladder40, including peripheral bond 43 and inflation bond 44. When moldportions 61 and 62 are placed in an overlapping configuration, ridges 63from mold portion 61 contact ridges 63 from mold portion 62. In someaspects of the invention, only one of mold portions 61 and 62 mayinclude ridges 63 so that the other of mold portions 61 and 62effectively has a planar configuration. Accordingly, the specificstructure of mold portions 61 and 62 may vary significantly.

With reference to FIG. 9A, one general step in the manufacturing processis depicted, in which two thermoplastic polymer sheets 71 and 72 areplaced between mold portions 61 and 62. As will be apparent from thefollowing discussion, sheets 71 and 72 respectively become first surface41 and second surface 42 for each of the bladders 40 formed with mold60. Accordingly, sheets 71 and 72 may be any of the various materialsdiscussed above for bladder 40.

With reference to FIG. 9B, another general step in the manufacturingprocess is depicted, in which mold portions 61 and 62 compress and bondsheets 71 and 72. More particularly, mold portions 61 and 62 translatetoward sheets 71 and 72 such that ridges 63 compress portions of sheets71 and 72. Portions of mold 60, particularly ridges 63, then emit radiofrequency energy such that the areas of contact between sheets 71 and 72are irradiated with a specific level of the radio frequency energy for apredetermined period of time. The radio frequency energy is absorbed bysheets 71 and 72 and the temperature of sheets 71 and 72 rises untilportions of sheets 71 and 72 melt, attain a glass transitiontemperature, or otherwise gain a temperature at which bonding may occur.Pressure applied to sheets 71 and 72 coupled with subsequent coolingforms a bond at the interface between sheets 71 and 72. Radio frequencybonding is one technique that may be utilized to bond sheets 71 and 72,thereby forming peripheral bond 43 and inflation bond 44. Other suitablebonding techniques include adhesive, thermal contact, laser, andinfrared welding.

With reference to FIG. 9C, yet another general step in the manufacturingprocess is depicted, in which the bonded sheets 71 and 72 are removedfrom mold 60. As discussed above, the various bladders 40 are formedadjacent to each other. Accordingly, each bond between sheets 71 and 72that is intended to form peripheral bonds 43 actually forms theperipheral bonds 43 for two adjacent bladders 40. A die or other cuttinginstrument is utilized, therefore, to bisect the various bonds betweensheets 71 and 72, thereby separating bladders 40 from each other. Inorder to ensure that bladders 40 remain connected, as in FIG. 7, only amajority of the various bonds between sheets 71 and 72 may be bisected.In addition, the bonds between sheets 71 and 72 that form inflation bond44 is also bisected to separate inflation area 45 from the centralportion of bladder 40. In some embodiments, mold 60 may be configured tobisect the bonds between sheets 71 and 72 following the irradiation withradio frequency energy.

Following bisection of the bonds between sheets 71 and 72, the variousbladders 40 are inflated. In order to inflate bladders 40, an inflationneedle, inflation nozzle, inflation electrode, or other inflation devicemay be coupled to inflation area 45 to inject the pressurized fluid. Thefluid then passes through the conduit formed between peripheral bond 43and inflation bond 44. Once bladder 40 is properly inflated with thefluid, inflation area 45 is sealed to seal the fluid within bladder 40.A further application of radio frequency energy or heat, for example,may be utilized to seal inflation area 45. As noted above, inflationbond 44 is bisected to separate inflation area 45 from the centralportion of bladder 40. During inflation, first surface 41 and secondsurface 42 will expand outward. Bisecting inflation bond 44 decouplesinflation area 45 from the central portion of bladder 40 and permitsinflation area 45 to remain at a constant position as first surface 41and second surface 42 expand outward.

As an alternative to the method discussed above, bladders 40 may also beformed through a blow molding process or a thermoforming process. In thethermoforming process, for example, sheets 71 and 72 are heated prior toplacement between mold portions 61 and 62. When mold 60 compressessheets 71 and 72 between ridges 63, bonding occurs at the specifiedlocations. In order to draw sheets 71 and 72 into the contours of mold60, a fluid may be injected between sheets 71 and 72. Air may also beremoved from the area between sheets 71 and 72 and mold portions 61 and62 through various vents in mold 60, thereby drawing sheets 71 and 72onto the surfaces of mold portions 61 and 62. That is, at least apartial vacuum may be formed between sheets 71 and 72 and the surfacesof mold portions 61 and 62.

FIG. 10 depicts an individual bladder 40 when removed from the pluralityof bladders formed through the process discussed above. In contrast withthe bladder 40 depicted in FIGS. 3-6C, the bladder 40 in FIG. 10includes two tabs 46. One of the tabs 46 extends from edge 51, and theother of the tabs 46 extends from edge 55. As discussed above, tab 46from one bladder 40 extends into the indentation 57 of an adjacentbladder 40. During manufacture, therefore, tabs 46 are part of thetessellation configuration of bladders 40. Once an individual bladder 40is removed from the plurality of joined bladders 40 depicted in FIG. 7,tabs 46 may be removed. Alternately, tabs 46 may be utilized as locatingpoints for positioning bladder 40 in a mold. That is, tabs 46 may assistin positioning bladder 40 in a mold that forms midsole 31, therebyassuring that bladder 40 is properly positioned and oriented in midsole31.

The shape of bladder 40 may vary significantly within the scope of thepresent invention.

Other modifications may also be made to bladder 40. For example,inflation bond 44 and inflation area 45 may be absent in someembodiments, as depicted in FIG. 11. In addition, bladder 40 may beincorporated into various products, in addition to footwear. Forexample, a plurality of bladders 40 may be utilized as packingmaterials. Bladders 40 may also be incorporated into seat cushions or abackpack or golfbag strap to enhance comfort. Accordingly, bladders 40may be utilized in a variety of applications.

Footwear 10 may also incorporate a bladder 80 in place of or in additionto bladder 40. The primary elements of bladder 80, as depicted in FIGS.12-14B, are an outer barrier 90 and a tensile member 95. Barrier 90 maybe formed of a polymer material and includes a first barrier layer 91and a second barrier layer 92 that are substantially impermeable to apressurized fluid contained by bladder 80. First barrier layer 91 andsecond barrier layer 92 are bonded together around their respectiveperipheries to form a peripheral bond 93 and cooperatively form a sealedchamber, in which tensile member 95 is positioned. First barrier layer91 forms an upper surface and a portion of a sidewall of bladder 80, andsecond barrier layer 92 forms a lower surface and another portion of thesidewall of bladder 80. This configuration positions peripheral bond 93at a midpoint of the sidewall. Alternately, peripheral bond 93 may bepositioned adjacent to the lower surface or the upper surface to promotevisibility through the sidewall. Accordingly, the specific configurationof barrier 90 may vary significantly within the scope of the presentinvention. Any of the thermoplastic polymer materials and fluidsdiscussed above for bladder 40 may be utilized for bladder 80.

Tensile member 95 may be formed as a textile structure that includes afirst wall 96, a second wall 97, and a plurality of connecting members98 anchored to each of first wall 96 and second wall 97. First wall 96is spaced away from second wall 97, and connecting members 98 extendbetween first wall 96 and second wall 97 to retain a substantiallyconstant spacing between walls 96 and 97. First wall 96 is bonded tofirst barrier layer 91, and second wall 97 is bonded to second barrierlayer 92. In this configuration, the pressurized fluid within thechamber formed by barrier 90 places an outward force upon barrier layers91 and 92 and tends to move barrier layers 91 and 92 apart. The outwardforce supplied by the pressurized fluid, however, extends connectingmembers 98 and places connecting members 98 in tension, which restrainsfurther outward movement of barrier layers 91 and 92. Accordingly,tensile member 95 is bonded to the interior surfaces of bladder 80 andlimits the degree to which barrier layers 91 and 92 may move apart uponpressurization of bladder 80. As an alternative to the textilestructure, tensile member 95 may also be a foam member located withinbladder 80 to limit the degree to which barrier layers 91 and 92 maymove apart upon pressurization.

A variety of techniques may be utilized to bond tensile member 95 toeach of first barrier layer 91 and second barrier layer 92. For example,a layer of thermally activated fusing agent may be applied to first wall96 and second wall 97. The fusing agent may be a sheet of thermoplasticmaterial, such as thermoplastic polyurethane, that is heated and pressedinto contact with first wall 96 and second wall 97 prior to placingtensile member 95 between barrier layers 91 and 92. The various elementsof bladder 80 are then heated and compressed such that the fusing agentbonds with barrier layers 91 and 92, thereby bonding tensile member 95to barrier 90. Alternately, a plurality of fusing filaments may beintegrated into first wall 96 and second wall 97. The fusing filamentsare formed of a material that will fuse, bond, or otherwise becomesecured to barrier layers 91 and 92 when the various components ofbladder 80 are heated and compressed together. Suitable materials forthe fusing filaments include, therefore, thermoplastic polyurethane orany of the materials that are discussed above as being suitable forbarrier layers 91 and 92. The fusing filaments may be woven or otherwisemechanically manipulated into walls 96 and 97 during the manufacturingprocess for tensile element 95, or the fusing filaments may besubsequently incorporated into walls 96 and 97.

The general shape of bladder 80, as depicted in FIGS. 12 and 13, ishexagonal.

Peripheral bond 93 effectively forms six edges 81-86 that sequentiallyextend around bladder 80. In contrast with bladder 40, each of edges81-86 have a linear configuration, but could have a convex, concave, orotherwise non-linear configuration. Tensile member 95 also has the shapeof a hexagon, and edges of tensile member 95 are spaced inward fromedges 81-86. In further embodiments, tensile member 95 may have a squareor round shape, for example.

Bladder 80 may have the configuration of a tessellation. With referenceto FIG. 15, a plurality of bladders 80 are depicted in a joinedconfiguration. In general, one of edges 81-86 of each bladder 80 ispositioned adjacent one of edges 81-86 of an adjacent bladder 80 to forma covering of an area, without significant gaps or overlaps, by aplurality of bladders 80 having a substantially similar shape. Variousshapes, whether hexagonal, rectangular, square, or triangular have theconfiguration of a tessellation. Other non-regular shapes may also havethe configuration of a tessellation. Although bladder 80 is discussedabove as having a generally hexagonal configuration, bladder 80 may alsohave a variety of other shapes that also have the configuration of atessellation. In some aspects of the invention, however, bladder 80 mayhave shapes that are not a tessellation. The advantages for formingbladder 40 in the form of a tessellation apply to bladder 80, includingmanufacturing efficiency, a limited amount of waste product, and energyefficiency.

In the joined configuration of FIG. 15, one of edges 81-86 of eachbladder 80 is positioned adjacent one of edges 81-86 of an adjacentbladder 80. During the manufacture of bladders 80, peripheral bonds 93of adjacent bladders may be formed as a single bond that is subsequentlybisected. Following bisection of the bonds between bladders 80, orbefore bisection, the various bladders 80 are inflated. An inflationarea 94 is formed by a bond that is adjacent to the periphery of bladder80. More particularly, inflation area 94 is formed at an intersection ofedges 81 and 86, but may be formed adjacent to any of edges 81-86 oradjacent any intersection of edges 81-86. In order to inflate bladders80, an inflation needle, inflation nozzle, inflation electrode, or otherinflation device may be coupled to inflation area 94 to inject thepressurized fluid. Once bladder 80 is properly inflated with the fluid,inflation area 94 is sealed to seal the fluid within bladder 80. Afurther application of radio frequency energy or heat, for example, maybe utilized to seal inflation area 94.

The shape of bladder 80 may vary significantly within the scope of thepresent invention, as discussed above. Other modifications may also bemade to bladder 80. For example, inflation area 94 may be absent in someembodiments. In addition, bladder 80 may be incorporated into variousproducts, in addition to footwear. For example, a plurality of bladders80 may be utilized as packing materials. Bladders 80 may also beincorporated into seat cushions or a backpack or golfbag strap toenhance comfort. Accordingly, bladders 80 may be utilized in a varietyof applications.

The present invention is disclosed above and in the accompanyingdrawings with reference to a variety of embodiments. The purpose servedby the disclosure, however, is to provide an example of the variousfeatures and concepts related to the invention, not to limit the scopeof the invention. One skilled in the relevant art will recognize thatnumerous variations and modifications may be made to the embodimentsdescribed above without departing from the scope of the presentinvention, as defined by the appended claims.

1. A method of manufacturing a plurality of bladders, the methodcomprising steps of: providing a first sheet and a second sheet of athermoplastic polymer material; locating a plurality of tensile membersbetween the first sheet and the second sheet; securing the tensilemembers to each of the first sheet and the second sheet; forming bondsbetween the first sheet and the second sheet and around the tensilemembers to thereby form the plurality of bladders, wherein the pluralityof bladders have sealed edges and are not in fluid communication withone another; and separating at least a portion of the bonds, wherein thestep of forming includes shaping the bonds to have a hexagonalconfiguration.
 2. The method recited in claim 1, wherein the step offorming includes shaping the bonds to have a tessellation configuration.3. The method recited in claim 1, further including a step of placing apressurized fluid within the plurality of bladders.
 4. The methodrecited in claim 1, further including a step of encapsulating at leastone of the bladders within a polymer foam material of a footwear solestructure.
 5. The method recited in claim 1, wherein the step of formingthe bonds includes forming a first bladder having a plurality of firstedges and at least one tensile member and a second bladder having aplurality of second edges and at least one tensile member.
 6. The methodrecited in claim 5, further comprising a step of sealing the firstbladder along the first edges and sealing the second bladder along thesecond edges.
 7. The method recited in claim 5, wherein the firstbladder and the second bladder are formed to be substantially identicalto each other.
 8. A method of manufacturing a plurality of bladders, themethod comprising steps of: providing a first sheet and a second sheetof a thermoplastic polymer material; locating a first tensile member, asecond tensile member, and a third tensile member between the firstsheet and the second sheet; securing the first, second, and thirdtensile members to each of the first sheet and the second sheet; formingbonds between the first sheet and the second sheet and around thetensile members so as to produce a plurality of joined bladdersincluding: (a) a first bladder incorporating the first tensile memberthat is bonded to opposite surfaces of the first bladder, the firstbladder having at least three first edges that define a tessellationshape for the first bladder, (b) a second bladder incorporating thesecond tensile member that is bonded to opposite surfaces of the secondbladder, the second bladder having at least three second edges thatdefine a tessellation shape for the second bladder, and (c) a thirdbladder incorporating the third tensile member that is bonded toopposite surfaces of the third bladder, the third bladder having atleast three third edges that define a tessellation shape for the thirdbladder, wherein one of the first edges is positioned adjacent andjoined to one of the second edges, another of the second edges ispositioned adjacent and joined to one of the third edges, and another ofthe third edges is positioned adjacent and joined to another of thefirst edges, and wherein the first, second, and third bladders havesealed edges and are not in fluid communication with one another; andbisecting at least a portion of the bonds.
 9. The method recited inclaim 8, wherein the forming step includes forming the bonds such thatthe first bladder, the second bladder, and the third bladder aresubstantially identical to each other.
 10. The method recited in claim8, wherein the forming step includes forming the bonds such that thefirst bladder has a hexagonal shape.
 11. The method recited in claim 10,wherein the first tensile member has a hexagonal shape.
 12. The methodrecited in claim 11, wherein the forming step includes forming the bondssuch that edges of the first tensile member are spaced from the firstedges of the first bladder.
 13. The method recited in claim 8, whereinthe first tensile member is formed from a textile material that includesa first wall bonded to the first sheet in the securing step, a secondwall bonded to the second sheet in the securing step, and a plurality ofconnecting members extending between the first wall and the second wall.14. The method recited in claim 8, further comprising: inflating thefirst bladder with a fluid under pressure; inflating the second bladderwith a fluid under pressure; and inflating the third bladder with afluid under pressure.
 15. A method of manufacturing a plurality ofbladders, the method comprising steps of: providing a first sheet and asecond sheet of a thermoplastic polymer material; locating a pluralityof tensile members between the first sheet and the second sheet, whereinthe tensile members are formed from a textile material and include apair of walls and a plurality of connecting members extending betweenthe walls; securing one wall of each of the plurality of tensile membersto the first sheet and one wall of each of the plurality of tensilemembers to the second sheet; forming bonds between the first sheet andthe second sheet and around the tensile members so as to produce aplurality of bladders, wherein each of the bladders has a tessellationconfiguration, wherein edges of a first bladder are positioned adjacentto edges of a plurality of second bladders, wherein the edges of thefirst bladder have a shape that mates with the edges of the plurality ofthe second bladders, wherein each of the first bladder and the pluralityof second bladders encloses one of the plurality of tensile members, andwherein the bonds are formed such that the first bladder and theplurality of second bladders are sealed and are not in fluidcommunication with one another; and bisecting at least a portion of thebonds.
 16. The method recited in claim 15, wherein the forming includesforming the bonds such that the first bladder and the second bladdershave a hexagonal configuration.
 17. The method recited in claim 16,wherein edges of the tensile members are spaced from edges of thebladders.
 18. The method recited in claim 15, wherein the bonds areformed such that the first bladder and the plurality of second bladdersare substantially identical to each other.
 19. The method recited inclaim 15, further comprising: inflating the first bladder with a fluidunder pressure; and inflating the plurality of second bladders with afluid under pressure.